Probably because Mr. Sugar wanted to embrace an all-round computer, to handle serious applications as well as the games. I don't know what would of happened if Amstrad had adopted Hardware Sprites, a C64 for example has 64k, but around 39k is usable, a CPC has 43k (tape based system) or 42k (when disc is introduced), so perhaps Hardware Sprites might of had a compromise on memory back then, which looks bad if you're trying to attract a serious users market as well as a gamers market. The CPC Plusses have Hardware Sprites though, but I've also read that there's a limitation on it.
There is an argument to say why didn't Amstrad get the Firmware right the first time? With clever use of it you can create Sprite like images & it works quite well for
@Morri game "Coolbox".
I started using this approach for my game "Get The Cash" and it was fine in the early versions of the game I wrote in
CPC BASIC 3, but when I started making the game more complicated, it wasn't challenging enough and needed something faster, so I went to Sean McManus' Easi-Sprite Driver, which made a huge difference. You can compare how the game differs by downloading the attached file in
Reply #5 with the file in
Reply #6.
In hindsight Hardware coding simply cannot be altered, so there is good examples of Firmware along with bad examples. My game shows that depending on what I wanted to do, the firmware was adequate enough for it, but when I wanted to complicate the process, it needed a software solution rather than a Hardware one. But once the Hardware coding was out there, it's difficult to simply update without causing problems.
The Firmware found in BASIC 1.1 adds onto what BASIC 1.0 has, but when the update was done in Firmware 1.1, some problems emerged for some early 464 programs.
This program I wrote, which does a Test on TXT RD CHAR reveals TXT RD CHAR operates slightly differently on a 464 from 6128, so in some of those early games which use TXT RD CHAR, there are problems and programs have to be modified so they can work on all computers, depending on what needs to be done to satisfy this depends on the game. I think some games are more complicated to resolve than others, depends on what the game does, the
Dambuster game which was harder with BASIC 1.1 (because all the bombs were destroying the Dam Wall), was somewhat easy to resolve with some IF statements.
So in a similar fashion, the CPC Plus adds-onto what the earlier CPCs have, by then all the machines add-onto the later Firmware, the Hardware Sprites no-doubt is seperate from the Firmware, but because it's Hardware like the firmware, limitations came out of it, which makes it difficult to simply replace I presume.